Locking mechanisms for couplings are used in a wide variety of industrial applications. Wherever separate segments of tubing must be joined together, especially those carrying fluids, a coupling and seal must be used.
Fabric reinforced hose and duct connectors are generally fastened to metal tubing that has a raised, circumferential bead at the end of the tube. This statement holds true for straight or bellows type hose and duct connectors. The flexible connector is able to stretch over the bead and is then secured to the duct by a commercial band clamp. The bead is intended to prevent the duct connector from slipping off of the tube by creating an interference between the band clamp and the bead. By tightening the band clamp around the duct connector, leakage from between the duct connector and the metal tube is supposed to be eliminated. However, when the band clamp is pulled in around the circumference it actually gathers the flexible duct material towards the band clamp screw and creates an axial channel that opens a leak path. Also, in the absence of some sort of bead or raised end on the duct connector itself, the duct can slide out from under the clamp due to the rubber coating of the duct connector taking a compression set.
In addition to the leaking problems, typically the locking mechanism comprises a metal ring with either a bolt type latch or an outwardly pivoting latch. Each of these designs has certain disadvantages associated with them. A bolting latch requires considerable time and manipulative effort to engage. Also, sometimes the bolting must be done in a confined area which makes the work even more difficult. An outwardly pivoting latch makes the coupling cross section substantially larger, and therefore, operating the latch in small openings becomes more difficult.
In view of these difficulties, there is a continuing need for a coupling and seal that eliminates the leakage path associated with existing seals, and there is a continuing need for a locking mechanism for a coupling and seal that is easy to engage and adds a minimum of increased width, while maintaining an effective coupling. A further need is a locking mechanism that can be engaged and disengaged in restricted space environments with one hand.